Cu-Mn Alloy Sputtering Target for Semiconductor Wiring
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Solution Overview
Problem
Conventional copper wiring in semiconductor devices faces contamination issues due to copper diffusion, requiring additional diffusion barrier layers that increase processing complexity and are not entirely effective in preventing copper diffusion.
Innovation Solution
A Cu-Mn alloy sputtering target with controlled Mn content (0.05 to 20wt%) and reduced impurities (Be, B, Mg, Al, Si, Ca, Ba, La, Ce) forms a self-diffusion suppression function, allowing for the formation of a manganese oxide barrier layer that inhibits copper diffusion and improves electromigration and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffusion barrier layer of Ta or TaN is formed to prevent copper diffusion, then copper diffusion prevention is improved, but processing steps and device complexity increase
Solution Approach 1:
The copper alloy wiring material contains Mn that automatically forms a manganese oxide barrier layer during heat treatment processes, enabling self-protection against copper diffusion without requiring separate barrier layer deposition steps. The alloying element Mn serves the dual function of strengthening the copper wiring and providing self-diffusion suppression.
Solution Approach 2:
The invention uses a composite copper alloy material containing Cu, Mn, and controlled impurity levels that combines the benefits of copper's low resistivity with Mn's ability to form protective oxide layers, replacing the need for separate Ta or TaN barrier layers.
2Reliability
If high purity copper is used to reduce resistivity, then electrical conductivity is improved, but copper diffusion and contamination increase
Solution Approach 1:
The invention changes the compositional parameters of copper by adding controlled amounts of Mn (0.01-10 wt%) and controlling impurity levels, which modifies the material's properties to provide both low resistivity and self-diffusion suppression capabilities.
Solution Approach 2:
The Mn distribution in the copper alloy creates local regions that preferentially oxidize to form barrier layers at the wiring interface, while the bulk copper maintains its excellent electrical conductivity properties.
3Reliability
If alloying elements are added to copper to improve EM resistance and corrosion resistance, then reliability is improved, but copper diffusion control becomes more difficult
Solution Approach 1:
The invention optimizes the concentration parameters of alloying elements, specifically limiting Mn to 0.01-10 wt% and controlling impurity levels, to achieve the right balance between EM/corrosion resistance and diffusion control characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Cu-Mn alloy sputtering target effectively prevents copper diffusion, simplifies the deposition process, and enhances the self-diffusion suppression function, achieving stable and uniform manganese oxide barrier formation on the copper alloy wiring, thereby improving the semiconductor wiring's performance and reducing processing complexity.
Implementation Method 1
forming a self-diffusion suppression function, allowing for the formation of a manganese oxide barrier layer that inhibits copper diffusion
Implementation Method 2
copper or copper alloy is thereafter subject to sputter deposition
Data Source
AI summary
Proposed is a Cu-Mn alloy sputtering target, wherein the Mn content is 0.05 to 20wt%, the total amount of Be, B, Mg, Al, Si, Ca, Ba, La, and Ce is 500wtppm or less, and the remainder is Cu and unavoidable impurities. Specifically, provided are a copper alloy wiring for semiconductor application, a sputtering target for forming this wiring, and a manufacturing method of a copper alloy wiring for semiconductor application. The copper alloy wiring itself for semiconductor application is equipped with a self-diffusion suppression function for affectively preventing the contamination around the wiring caused by the diffusion of active Cu, improving electromigration (EM) resistance, corrosion resistance and the like, enabling and facilitating the arbitrary formation of a barrier layer, and simplifying the deposition process of the copper alloy wiring for semiconductor application.